Exercise 1: Editing the Grading Elevation
Procedure
 
 
 

In this exercise, you will edit the elevation of a grading baseline. The grading adjusts to reflect the elevation change.

For more information, see the AutoCAD Civil 3D Help topic Editing Grading Criteria.

Edit feature line elevations

  1. Open Grading-4.dwg, which is located in the tutorial drawings folder.

    This drawing contains a rectangular building pad graded to the surrounding surface at a 3:1 slope. Where the slope pattern is green, it is a fill slope in which the grading slopes down from the pad to the surface. Where the slope pattern is red, it is a cut slope in which the grading slopes up from the pad.

  2. Click Modify tabEdit Elevations panelElevation Editor .
  3. In the drawing, select the baseline for the grading (rectangular line).
    NoteThe surface style for the building pad grading has borders turned off, making it easier to select the baseline. Otherwise, the surface border would be on top of the baseline.

    The Elevation Editor shows the following grading settings for each corner of the feature line in a clockwise direction. The starting point is the upper left corner.

    • Station — Distance from the start of the feature line.
    • Elevation — Elevation of the current point.
    • Length — Distance to the next point.
    • Grade Ahead — Grade toward the next point. Adjusting this setting holds the elevation of the current point and adjust the elevation of the next point for the new grade.
    • Grade Back — Grade from the previous point. Adjusting this setting affects the elevation of the current point, holding the elevation of the next point for the new grade.

    Further exploration: Another way to review and edit the elevations of a feature line is to click Modify tabEdit Elevations panelElevation Editor . A triangular marker is displayed at the starting point of the feature line. Press Enter to move to the next point. You can edit data on the command line.

  4. In the Grading Elevation Editor, Shift+click the second and third rows to select them.
  5. Double-click the elevation value in one of the rows and change it to 730 feet.

    Both of the selected rows’ elevation values change to 730 feet. Notice that the shape of the grading and the Grade Ahead and Grade Back values have changed to reflect the elevation change.

Edit feature line grades

  1. Select the first three rows in the table. Click Flatten Grade or Elevations.
  2. In the Flatten dialog box, select Constant Grade. Click OK.

    The first two points are set to the same grade, 2.693%, and the shape of the grading changes in response to the elevation change. Flattening the grade holds the elevation values of the first and last selected points and modifies elevations of the points in between.

  3. Click Show Grade Breaks Only.

    The second station’s row is hidden, because there was no difference in grade between it and the previous station.

  4. In the first row, change the Grade Ahead value to -3.000%.
  5. Click Show Grade Breaks Only.

    Notice that the second station’s grade has changed to reflect the change you made in step 4.

  6. Click to close the Grading Elevation Editor.

To continue this tutorial, go to Exercise 2: Balancing Cut and Fill Volumes.